Congenital heart disease occurs in approximately six to ten children born out of one thousand. In general terms, congenital heart defects are abnormalities in heart structure formation arising during fetal development. While symptoms of such defects may become apparent following childbirth or early childhood, the presence of such defects, and symptoms arising therefrom, may not be recognized until well later into adulthood.
Congenital heart defects include, for example, Atrial Septal Defects (ASDs), Ventricular Septal Defects (VSDs), and Patent Ductus Arteriosis (PDA). Generally speaking, defects in the septum such as ASDs and VSDs are some of the most commonly occurring congenital heart defects. For reference, the septum is composed of muscular tissue and acts to divide the heart into left and right sides. More specifically, the septum includes an atrial septum and a ventricular septum. As the name indicates, ASDs include improper formation of the atrial septum, the wall separating the right atrium and the left atrium. VSDs are generally a hole or other defect in the ventricular septum, the wall separating the right ventricle and the left ventricle. The presence of such congenital heart defects can result in relatively mild symptoms such as decreased energy, shortness of breath, or increased rate of fatigue. However, congenital heart defects can also lead to more serious problems including heart failure, irreversible pulmonary vascular disease, or paradoxic embolization.
One type of ASD is a Patent Foramen Ovale (“PFO”). During fetal development a passageway for blood exists between a septum primum and a septum secundum, which later combine to form the atrial septum. This passage, or opening, is used during fetal development to facilitate blood flow between the two atria in a growing fetus. In non-defective hearts, the opening closes following childbirth due to increased pressure on the left side of the heart. However, in instances where the atrial septum is defective, the passageway remains active after childbirth. This residual opening is a Patent Foramen Ovale. PFOs can be said to act like selective valves in many cases. In operation, the “valve” might only open under certain pressure conditions. For instance, pressure exerted on the heart when a person is sneezing or otherwise straining himself or herself can cause reverse blood flow through a PFO.
In the past, congenital heart defects have largely been treated through open-chest surgery or other invasive procedures requiring access through the chest or torso. Closure, or alternatively occlusion, of some congenital defects has also been accomplished utilizing percutaneous techniques. In particular, a transcatheter approach has been utilized to deliver occlusion devices for ASDs, PDAs, PFOs, and VSDs, for example. Generally, these occlusion devices are delivered to a septal defect and then expanded within the defect in order to both occlude the defect, and anchor the occlusion device in a desired position.
However, the occlusion device technologies mentioned above are potentially hampered by inherent shortcomings. For example, occlusion devices are often limited to use with centrally located defects having both well-defined margins and limited sizes. Furthermore, implantation failures including device migration, embolization, and residual shunts occur at undesirable levels. Indeed, repair of such failures can require emergency open chest surgery. Additionally, holes at the bottom of the atrial septum and large holes in the middle of the atrial septum can be problematic to occlusion device use, and may still require open chest surgery in order to either suture a defect closed, or suture a patch to the defect.
While catheter-based methods can include the shortcomings mentioned above, open chest surgery is still less desirable than less invasive catheter-based methods. In particular, during open chest surgery the heart is normally put under cardioplegic arrest with circulation maintained by cardiopulmonary bypass. The invasiveness of such procedures, as well as stoppage of the heart, drastically increases the risks of death and prolonged recovery. As such, a need exists for methods and associated devices capable of repairing congenital defects via less invasive means, including repairing those defects not amenable to the use of occlusion devices. More specifically, a need exists for a method and apparatus capable of allowing a surgeon to suture a septal defect, or suture a patch to a septal defect, utilizing a catheter delivery method.